The present invention relates to a cyclone dust collector for collecting various foreign matters, such as dust by using a cyclone principle, and more particularly, to a multi-cyclone dust collector, in which a cyclone operation is repeated for improving a dust collecting performance.
In general, the cyclone dust collector separates and collects foreign matters from air by using centrifugal force, and is applied to a domestic vacuum cleaner. Of different types of cyclone dust collectors, a multi-cyclone dust collector, in which a primary cyclone dust collecting device and a secondary cyclone dust collecting device are connected to for one unit of cyclone dust collector for multi-stage foreign matter collection, can provide an excellent dust collecting performance than a single cyclone dust collector with one cyclone device. That is, the primary cyclone dust collecting device collects foreign matters of comparatively great size, and the secondary dust collecting device collects fine foreign matters collection of which are unable by means of the primary cyclone dust collecting device. FIGS. 1 and 2 illustrate one example of the multi-cyclone dust collector, referring to which the multi-cyclone dust collector will be explained.
The multi-cyclone dust collector is provided with a primary cyclone dust collecting part 1, and a secondary cyclone dust collecting part 2 inside of the primary cyclone dust collecting part, a fan 3 for drawing air through respective cyclone parts, a fan motor 4 for driving the fan 3. The primary cyclone dust collector 1 is provided with an outer shell 1a forming a body of the primary cyclone dust collector 1 and serving as a dust collecting vessel, a first air inlet 1b formed in one side of an upper portion of the outer shell for drawing room air, and a first air outlet 1c. And, the secondary cyclone dust collecting part 2 is provided with an inner body 2a spaced from an inside of the outer shell 1a of the primary cyclone dust collecting part, a second air inlet 2b for air inlet into the inner body 2a, and a second air outlet 2c for discharging air from the inner body. The second air inlet 2b is designed to be in communication with the first air outlet 1c in the primary dust collecting part 1 for leading air to flow from the primary cyclone dust collecting part 1 to the secondary dust collecting part 2. The second air outlet 2c is in communication with a space where the fan 3 and fan motor 4 are disposed. The inner body 2a has a cone shape with a diameter become the smaller as it goes downward, and there is a dust collecting part 2d under the inner body 2a for collecting fine dust separated from the air. The dust collecting part 2d is separated from a bottom portion of the primary cyclone dust collecting part 1 by an additional partition 2e. Accordingly, the fan motor 4 drives the fan 3 to draw air from the first air inlet 1b via the second air outlet 2c, the second air inlet 2b, and the first air outlet 1c. The air drawn into the outer shell 1a circulates along an inner side of the outer shell 1a and an outer side of the inner body 2a, together with dust, during which the air drawn into the inner body 2a through the first air outlet 1c, and the dust is collected at the bottom of the outer shell 1a. However, as fine dust, so light to be separated by a centrifugal force of the first cyclone dust collecting part, is drawn into the inner body 2a through the first air outlet 1c together with the air, and separated in the inner body 2a during the air and dust circulate around the inner body 2a The dust separated from the air thus is dropped down by its weight and collected in the dust collecting part 2d, and the air, as it rises along a center portion of the inner body 2a, is discharged to the space where the fan 3 and fan motor 4 are located through the second air outlet 2c. However, the cyclone dust collector has the following problems in view of the structure.
First, a dust collecting capacity of the primary cyclone dust collecting part 1 has been comparatively small. That is, the disposal of the secondary cyclone dust collecting part 2 in the primary cyclone dust collecting part 1 causes a problem in that the dust collecting capacity of the primary cyclone dust collecting part 1 which should collect large sized dust becomes small, that in turn causes an inconvenience of frequent dust removal.
Second, if there is continuous inflow of much dust into the secondary cyclone dust collecting part 2 in comparison to the dust collecting capacity of the secondary cyclone dust collecting part 2, excessive dust over the dust collecting capacity passes through the secondary dust collecting part 2 and enters into the fan motor 4. This is because the cyclone dust collector is designed such tat the primary cyclone dust collecting part 1 collects large sized dust while the fine dust is discharged to the secondary cyclone dust collecting part 2. That is, even though it is desirable that the primary cyclone dust collecting part 1 collects dust as much as possible including the fine dust, the primary cyclone dust collecting part fails it, to cause frequent failure of the fan motor, and to require frequent removal of collected dust Third, in removal of the fine dust collected in the dust collecting part 2d done by removing the inner body 2a from the outer shell 1a and removing the dust through an opening for the inner body 2a, the partition 2e impedes a smooth removal of the fine dust, to cause inconvenience to the user and bad smell of decomposed dust remained in the dust collecting part 2d. 
An object of the present invention is to provide a multi-cyclone dust collector, of which primary cyclone dust collecting part can collect dust as much as possible including fine dust for preventing damage to the fan motor in advance.
Another object of the present invention is to provide a multi-cyclone dust collector which can remove the collected dust smoothly.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the multi-cyclone dust collector includes a primary cyclone body and dust collecting box for causing circulation of air and collecting various foreign matters, the primary cyclone body and dust collecting box having a first air inlet for drawing air together with various foreign matters and a first air outlet for discharging air from which the various foreign matters are removed primarily, a secondary cyclone body over the primary cyclone body and dust collecting box for causing circulation of the air to flow in a direction at a right angle to the direction of air flow in the primary cyclone body and dust collecting box, the secondary cyclone body having a second air inlet in communication with the first air outlet for drawing the air from the primary cyclone body and dust collecting box to the secondary cyclone body in a direction tangential to an inside circumference of the secondary cyclone body, and a second air outlet in a center of one side of the secondary cyclone body in the vicinity of the first air outlet having an extension piece to inside of the secondary cyclone body in communication with a space where the fan is located, and a second dust collecting box having an opening to the other side of the second air inlet.
In other aspect of the present invention, there is provided a dust collecting box in a cyclone dust collector for drawing air together with foreign matters, separating the foreign matters from the air by a cyclone principle, and collecting the separated foreign matters in a dust collecting box, including a partition plate inside of the dust collecting box for dividing the dust collecting box into an upper portion and a lower portion and providing a gap between the partition plate and the inside wall surface of the dust collecting box.